Ruby is an interpreted scripting language for quick and easy
object-oriented programming.

The Ruby DNS resolver library, resolv.rb, used predictable transaction IDs
and a fixed source port when sending DNS requests. A remote attacker could
use this flaw to spoof a malicious reply to a DNS query. (CVE-2008-3905)

A number of flaws were found in the safe-level restrictions in Ruby. It
was possible for an attacker to create a carefully crafted malicious script
that can allow the bypass of certain safe-level restrictions. (CVE-2008-3655)

A denial of service flaw was found in Ruby's regular expression engine. If
a Ruby script tried to process a large amount of data via a regular
expression, it could cause Ruby to enter an infinite-loop and crash.
(CVE-2008-3443)

Users of ruby should upgrade to these updated packages, which contain
backported patches to resolve these issues.

4. Solution:

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.